Spark-plug.



A. SCHMIDT.

SPARK PLUG.

APPLIGATION ULEB Hm.. 16, 1912.

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ALBERT SCHMIDT, OF FLINT, MICI-IIGAN, ASSIGNOR 'IO CHAMPION IGNITION COMPANY, 0F FLINT, MICHIGAN, A CORPORATION OF MICHIGAN.

SPARK-PLUG.

Y Specification of Letters Patent.

. Patented May 27,1913.

Application led March 16, 1912, Serial No. 684,117.

To all whom/t may concern.'

Be it known that I, ALBERT SCHMIDT, a citizen of the Republic of France, residing at Flint, in the county of Genesee and State ofMichigan, have invented certain new and useful Improvements in Spark-Plugs, vof which the following is a specification, reference being had therein to the accompanying drawings. j f

The invention relates to spark plugs and has for its main object the avoidance of breakage of the insulators due to sudden jolts or jars to which the machine may be subjected.

In the present state of the art lit is usual to employ in spark plugs, electric currents of high voltage and consequently there is danger of short circuiting. To avoid this danger it is usual to provide the insulators with a portion of considerable length projecting out from the metallic casing so as to produce a sufficient air gap between the case and the connector for the electrode to avoid short lcircuiting by jumping. This projecting portion of the insulator is' however, frequently broken olf due to some sudden jolt or jar such as frequently occur with motor vehicles.

The present invention isn designed to overcome this diliioulty by dispensing with the projecting po-rtion of the insulator and at( the same time securing effective insulation,

the construction being as follows:

In the drawings, Figure l is a central longitudinal section through 'the spark plug; Fig. 2 is a cross section. on line Fig, l.

A is the metallic outer casing of a spark plug and B is the insulator in which the electrode C is secured. l

D is the clamping sleeve for securing the insulator B in the case. The insulator B instead 4of projecting beyond the case to provide the necessary spacing, is cut-ott, but short circuiting is avoided by providing an insulating 'lining for the case. Thus as shown, the .insulator B projects but slightly beyond the metallic sleeve D and the latter is provided with an insulating lining E which also preferably forms a hood for inclosing the end of the insulator B. The lining E may be secured within the sleeve D by any suitable means but as shown the sleeve has an outwardly extending thinflange F which is'peened over. ashoulder G `on the insulator lining, holding the latter from displacement and also forming a water proof joint. The portion of the lining E which projects beyond the sleeve F is of much greater diameter than is usualwith the projecting insulators of spark plugs and the cross section is sufficient to withstand the jolts and jars without danger of breaking.

-The insulator B may be secured within the case A by any suitable means but as shown. a metallic ring H is arranged about a bead or enlargement of the body 'of the insulator and is secured thereto by peening one end of the ring over the bead. The ring II is then clamped by having one end thereof bearing against the shoulder I on the case while the other end J is engaged by the clamping sleeve D.

In use, sho-rt circuiting of the current is prevented between the electrode and the me tallic case by the lining E which extends for a sufficient distance to make a safe air gap between the metal'of the electrode and `the metalof the case. At the same time danger' of breakage of the. insulator is avoided Qby the reduced length of the projecting portion thereof, and further by tapering this projecting portion so as to reduce its mass and provide the largest section at the point of attachment. j What I claim as my invention is:

l.. In a spark plug, the combination with a metallic case, of an electrode insulator within said ease having an enlarged central portion anda tapering end portion, securing inea-ns for said electrode insulator engaging the enlarged portion thereof, a me tallic clamping sleeve for said securing vmeans engaging' said case, and an insulator lining foi' said clamping sleeve surrounding said electrode insulator and spaced thereffroin. j j,

Q. In a spark plug, the combination with a metallic case, of an electrode insulator having an enlarged central portion and tapering end portions, a metallic ring surrounding said enlarged central portion and having a gas tight engagement therewith, a. metallic clamping sleeve engaging said. case and clamping said ring` against a shoule der on the case, and an insulator lining within said metallic sleeve surrounding said electrode insulator and spaced therefrom.

3. In a lspark plug, the combination with apmetallic case, of an electrode-an insulator ilo" for the electrode arranged Within said case, a metallic Clamping sleeve for securing said insulator Within the case, and an insulator lining for said metallic sleeve surroumfling and spaced from said electrode insulator, said lining being secured to the metallic sleeve independent of the electrode.

4. In a spark plug, -the combination with a metallie-ease, of an electrode insulatoi` Within said ease, a `metallic ring engaging the insulator and seated in the case, a metallio clamping sleeve engaging said case and clamping the 4ring to its` seat, and an insulator lining Within said metallic sleeve and surrounding said electrode insulator.

5. In a spark plug, the combination With a metallic case, of an electrode insulator wit-hin the ease having an enlarged portion, a metallic ring secured to the insulator and seated in Said case, a met-allie sleeve engaging said case andclamping the ring to its seat, and an insulator lining Within said metallie sleeve and surrounding said insulator, said insulator lining and the metallic sleeve being secured together by a shoulder and socket joint.

In testimony whereof I aiix my signatur in presence of two Witnesses.

' ALBERT SCHMIDT. Witnesses.:

MAGIBEL BRICKER,

F. J. UTLEY. 

